The present invention relates to the processing of tobacco materials and mixtures thereof with other materials, and in particular to the processing of such materials using extrusion means.
Cured tobacco leaf conventionally undergoes several processing steps prior to the time that the resulting cut filler is provided. For example, tobacco leaves are threshed in order to separate the tobacco laminae from the stem. The tobacco laminae undergo further processing resulting in cut filler, while the stems are discarded or employed in the manufacture of reclaimed tobacco products which are traditionally of relatively low quality.
The handling, threshing and storing stages of conventional tobacco leaf processing steps result in the formation of considerable amounts of wasted tobacco material. In particular, typical processing conditions cause the formation of relatively large amounts of dust and fines. Such dust and fines are of such a small size as to be of essentially no use in the manufacture of cigarettes. However, it is possible to retrieve some of the dust and fines, and employ these materials with tobacco stems in the manufacture of reclaimed tobacco materials.
Methods for providing reclaimed, reconstituted or processed tobacco materials are proposed in U.S. Pat. Nos. 1,016,844 to Moonelis; 1,068,403 to Maier; 2,708,175; 2,845,933 and 3,009,835 to Samfield et al; 2,734,509 to Jurgensen; 2,734,513 to Hungerford et al; 2,769,734 to Bandel; 3,053,259 and 3,209,763 to Parmele et al; 3,203,432 to Green et al; 3,398,754 to Tughan; 3,410,279 to Mosby et al; 3,464,422 to Herbert; 3,540,456 to McGlumphy et al; 4,325,391 to Schmidt; and 4,542,755 to Selke et al.
Methods for providing tobacco materials in lap-bonded, laminated or extruded form are proposed in U.S. Pat. Nos. 4,236,538 to Foster et al; 3,870,054 to Arledter et al; 4,416,295 to Greig et al; 4,598,721 to Stiller et al; 3,932,081 to Buchmann et al; 4,510,950 to Keritsis et al; and EPO Patent Application No. 167,370 to Demitrios et al.
It would be highly desirable to provide an efficient and effective process for providing processed tobacco materials which are co-extruded in the form of a sheet having a multi-layered structure.